The present invention relates to arc welding which uses a continuous feed of a consumable wire electrode and more particularly to such continuous arc welding where lateral movement is imparted to the arcing end of the electrode.
Continuous arc welding as above defined has been used for a long time, especially in connection with automatic welding processes. Specified welding processes are first defined as to the manner in which the arcing electrode is protected from oxidation. A popular process is known as gas metal arc (GMA) where the arc is protected by an inert gas. In another process, submerged arc welding, the arc is submerged in a flux puddle. The flux may be applied by a separate mechanism or provided by using a flux core electrode wire. The use of selected gases and blends of gases and selected fluxes is a highly developed art and it is possible to obtain good welds with practically any type of metal or alloy of metals.
Once the gas or flux is selected, the problems encountered in a welding operation lie in the preparation of the joint or slot between the pieces to be welded together, the selection of wire size, the amount of current to be applied and, in an automatic operation, the rate of wire movement into the slot and the rate of movement of the torch along the slot. Also, there must be a determination as to whether a single pass or several passes are best for the job. These, and other considerations make continuous arc welding more of an art than a science and set-up problems are often encountered especially with automatic equipment. The variables not only have to be established at the beginning of a welding operation but also have to be adjusted during the welding, as for example, when the width of the slot changes. A number of refinements have been developed in welding equipment to overcome the problems encountered, especially in automatic equipment. There is, nevertheless, room for further improvement and one area of improvement relates to the manner in which metal is transferred from the electrode to the walls of the slot.
My U.S. Pat. No. 4,177,373, dated Dec. 4, 1979, entitled "Oscillation Arc Welding" discloses a significant improvement in metal transfer from the electrode to the walls of the slot. The consumable electrode is oscillated in the slot between the two pieces being welded together, with the further feature of producing a sudden stop or impact at each end of the oscillation path. This impact impels drops of molten metal from the electrode to the sides of the slot. This oscillation movement impelling drops of metal against the slot walls as fast as they form provides for a significant improvement in many welding operations over conventional procedures where drops of metal are dispersed in a more random manner by the action of gravity and the arcing current known as the Lorenz effect.